• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.685-686
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• 2023

상수도관의 수질 및 부식도 검사에는 파이프에 손상을 입히지 않고 지속적인 방법이 필요하다. 초음파는 이를 만족하면서 상태를 확인할 수 있고 주파수가 높을수록 해상도가 좋아져 정밀한 측정이 가능하다는 장점이 있다. 이러한 특성을 이용해 상수도관 모니터링 시스템으로 초음파 기반의 Scanning Acoustic Microscopy(SAM)과 Convolutional Neural Network(CNN)을 사용하는 새로운 방법을 제안한다. 기존의 Non-Destructive Testing(NDT)방식의 단점을 보완하면서 더 높은 해상도로 상수도관을 점검하는 방식으로, SAM 을 이용하여 부식으로 인한 파이프 두께 변화와 부유물의 여부 및 수질을 동시에 감지하고 얻은 데이터를 CNN 으로 분석했다. CNN 의 높은 정확도 결과로 이 시스템의 파이프 부식도 및 수질 모니터링에 대한 적합성을 보여주었다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.4
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• pp.374-381
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• 2024

This paper delves into the application of the short-wave infrared (SWIR) region, with a focus on the synthesis and optical characteristics of silver sulfide (Ag₂S) nanostructures. SWIR offers advantages such as reduced damage to biological tissues and enhanced optical transparency, making it valuable across various domains. The study introduces three distinct synthesis methods, each showcasing the ability to obtain nanostructures with improved optical properties. These research findings open up the possibility of providing tailored solutions in detection, imaging, and other applications by controlling the size and ligands of Ag₂S nanoparticles. This paper provides new insights into the utilization of Ag₂S in the SWIR region, which is expected to foster advancements in future technologies.

• Radiation Oncology Journal
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• v.20 no.1
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• pp.41-52
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• 2002

Purpose : 3D conformal radiotherapy, the optimum dose delivered to the tumor and provided the risk of normal tissue unless marginal miss, was restricted by organ motion. For tumors in the thorax and abdomen, the planning target volume (PTV) is decided including the margin for movement of tumor volumes during treatment due to patients breathing. We designed the respiratory gating radiotherapy device (RGRD) for using during CT simulation, dose planning and beam delivery at identical breathing period conditions. Using RGRD, reducing the treatment margin for organ (thorax or abdomen) motion due to breathing and improve dose distribution for 3D conformal radiotherapy. Materials and Methods : The internal organ motion data for lung cancer patients were obtained by examining the diaphragm in the supine position to find the position dependency. We made a respiratory gating radiotherapy device (RGRD) that is composed of a strip band, drug sensor, micro switch, and a connected on-off switch in a LINAC control box. During same breathing period by RGRD, spiral CT scan, virtual simulation, and 3D dose planing for lung cancer patients were peformed, without an extended PTV margin for free breathing, and then the dose was delivered at the same positions. We calculated effective volumes and normal tissue complication probabilities (NTCP) using dose volume histograms for normal lung, and analyzed changes in doses associated with selected NTCP levels and tumor control probabilities (TCP) at these new dose levels. The effects of 3D conformal radiotherapy by RGRD were evaluated with DVH (Dose Volume Histogram), TCP, NTCP and dose statistics. Results : The average movement of a diaphragm was 1.5 cm in the supine position when patients breathed freely. Depending on the location of the tumor, the magnitude of the PTV margin needs to be extended from 1 cm to 3 cm, which can greatly increase normal tissue irradiation, and hence, results in increase of the normal tissue complications probabiliy. Simple and precise RGRD is very easy to setup on patients and is sensitive to length variation (+2 mm), it also delivers on-off information to patients and the LINAC machine. We evaluated the treatment plans of patients who had received conformal partial organ lung irradiation for the treatment of thorax malignancies. Using RGRD, the PTV margin by free breathing can be reduced about 2 cm for moving organs by breathing. TCP values are almost the same values $(4\~5\%\;increased)$ for lung cancer regardless of increasing the PTV margin to 2.0 cm but NTCP values are rapidly increased $(50\~70\%\;increased)$ for upon extending PTV margins by 2.0 cm. Conclusion : Internal organ motion due to breathing can be reduced effectively using our simple RGRD. This method can be used in clinical treatments to reduce organ motion induced margin, thereby reducing normal tissue irradiation. Using treatment planning software, the dose to normal tissues was analyzed by comparing dose statistics with and without RGRD. Potential benefits of radiotherapy derived from reduction or elimination of planning target volume (PTV) margins associated with patient breathing through the evaluation of the lung cancer patients treated with 3D conformal radiotherapy.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.4
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• pp.309-322
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• 2007

This study deals with the irradiation effects on some selected components which are being used in an Advanced Spent Fuel Conditioning Process (ACP). Irradiation test components have a higher priority from the aspect of their reliability because their degradation or failure is able to critically affect the performance of an ACP equipment. Components that we chose for the irradiation tests were the AC servo motor, potentiometer, thermocouples, accelerometer and CCD camera. ACP facility has a number of AC servo motors to move the joints of a manipulator and to operate process equipment. Potentiometers are used for a measurement of several joint angles in a manipulator. Thermocouples are used for a temperature measurement in an electrolytic reduction reactor, a vol-oxidation reactor and a molten salt transfer line. An accelerometer is installed in a slitting machine to forecast an incipient failure during a slitting process. A small CCD camera is used for an in-situ vision monitoring between ACP campaigns. We made use of a gamma-irradiation facility with cobalt-60 source for an irradiation test on the above components because gamma rays from among various radioactive rays are the most significant for electric, electronic and robotic components. Irradiation tests were carried out for enough long time for total doses to be over expected threshold values. Other components except the CCD camera showed a very high radiation hardening characteristic. Characteristic changes at different total doses were investigated and threshold values to warrant at least their performance without a deterioration were evaluated as a result of the irradiation tests.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.5
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• pp.476-486
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• 2004

This paper is the second part of the study on the development of a smart active layer (SAL) sensor, which consists of two parts. As mentioned in the first paper, structural health monitoring (SHM) is a new technology that is being increasingly applied at the industrial field as a potential approach to improve cost and convenience of structural inspection. Recently, the development of smart sensor is very active for real application. This study has focused on preparation and application study of SAL sensor which is described with regard to the theory and concept of the SAL sensor in the first paper. In order to detect elastic wave, smart piezoelectric sensor, SAL, is fabricated by using a piezoelectric element, shielding layer and protection layer. This protection layer plays an important role in a patched network of distributed piezoelectric sensor and shielding treatment. Four types of SAL sensor are designed/prepared/tested, and these details will be discussed in the paper In this study, SAL sensor ran be feasibly applied to perform structural health monitoring and to detect damage sources which result in elastic waves.

• Journal of Plant Biology
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• v.36 no.4
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• pp.383-389
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• 1993

The effects of light and $CO_2$ on the electrophysiological characteristics of guard cells in the intact leaf and in the detached epidermis have been investigated. Guard cells in intact leaves showed the membrane hyperpolarization in response to light. The biggest induced change of the membrane potential difference (PD) in the guard cells of the intact leaf was 13 m V by light and 42 mV by $CO_2$ in Commelina communis. Similar results were obtained with Tradescantia virginiana. However, there were no changes of membrane PD in detached epidermis. In order to determine the influence of the mesophyll on the changes of membrane PD, infiltration of the mesophyll cells with photosynthetic inhibitors was performed. In CCCP infiltrated leaf discs the guard cell membrane was depolarized slightly by red-light and hyperpolarized by $CO_2$, but in leaf discs infiltrated with DCCD and DCMU the guard cell membrane was hyperpolrized by both red-light and $CO_2$ as the control leaf discs. In azide infiltrated leaf discs the guard cell membrane showed no response to light and there was a much reduced membrane hyperpolarization by $CO_2$ compared to other responses. It was likely that azide caused leaf damage and the activity of cell metabolism was decreased greatly, resulting in small membrane PD changes by $CO_2$ and no changes by redlight. Therefore, it can be suggested that red light was sensed by the mesophyll and the light induced guard cell membrane hyperpolarization was related to energy produced by cyclic-photophosphorylation, but ${CO_2}-induced$ guard cell membrane hyperpolarization was not related to photosynthesis. Alkalisation of the vacuole was observed when the intact leaf was exposed to $CO_2$, indicating that membrane hyperpolarization was mainly the result of proton efflux.efflux.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.1
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• pp.9-16
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• 2020

The aim of this study is to investigate visual exploration of children and adolescents during dental treatment by examining time ratio of eye opening in various age groups. This study reviewed 5 - 15 year-old patients who visited the department of pediatric dentistry of Yonsei University Dental Hospital from March to October 2018. Restorative treatment or sealant application was done by one pediatric dentist. A trained observer used 2 stopwatches to measure total treatment time and time of open eye. Average ratios of eye opening were calculated and compared. 60 patients were investigated, with 15 patients in each age group. Average ratio of eye opening increased as age decreased (p < .001). The average of 13 - 15 year-olds was significantly shorter than that of children younger than 12 years (p < .005). This study indicated that children have higher rates of eye opening during dental treatment than adolescents.

• Journal of Korea Multimedia Society
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• v.7 no.7
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• pp.896-904
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• 2004

In this paper, We present an efficient variable rate speech coder for spectral efficiency and packet processing technique for packet loss compensation of a voice codec with 10msec frame in VoIP service. Through disconnecting the users from the spectral resource during silence interval of about 60% period, a variable rate voice coder based on a voice activity detection(VAD) can increase spectral gain by two times. The performance of the method was analyzed by variation of detected voice activity factor and degraded speech frame ratio under various background noise level, and compared those of G.729B of ITU-T 8kbps standard speech codec. A method to compensate lost packets utilized addition of recovery data to a main stream and error concealment scheme for speech quality enhancement, the performance is verified by reconstructed speech quality. The proposed scheme can achieve spectral gain by two times or enhance speech quality by 3dB through reserved bandwidth of VAD. Therefore, the proposed method can enhance a spectral efficiency or speech quality of VoIP.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.3
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• pp.103-110
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• 2016

Recently, structural health monitoring system(SHMS) has been appled cable bridges as the effective maintenance tool and the management threshold is considered to assess the status of the bridge in SHMS. The threshold is generally determined by the allowable limit based on design specification because there is no method and standard for threshold calculation. In case of the conventional thresholds, it is difficult to recognize the event, abnormal behavior and gradual damage within the threshold. Therefore, this study reviewed the problem of previous methods and proposed the advanced methodologies based on probabilistic approach for threshold calculation which can be applied to practice work. Gumbel distribution is adopted in order to calculate the threshold for caution and warning states considering the expectations for return periods of 50 and 100 years. The thresholds were individually determined for measurement data and data variation to detect the various abnormal behaviors within allowable range. Finally, it has confirmed that the thresholds by the proposed method is detectable the abnormal behavior of real-time measuring data from SHMS.

• The Journal of Dong Guk Oriental Medicine
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• v.7 no.1
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• pp.65-74
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• 1998

We investigated the in vivo effect of an aquous extract from Rhois Galla (R-G) on glucokinase and hexokinase activities of diabetes mellitus induced by interleukin-$1{\beta}$ ($IL-1{\beta}$). After 1 week of alloxan injection, the levels of serum glucose and insulin secretion were dramatically increased, however, the insulin secretion was decreased with administration of R-G. $IL-1{\beta}$ injection allowed the serum glucose level increased and the level was decreased by R-G administration. Furthermore, we could observe that R-G was effective in recovering the levels of insulin secretion. Enzyme activities of the glucokinase and hexokinase were decreased by $IL-1{\beta}$ treatment In contrast, R-G administration to the mice allowed proportion increasing. Seemingly, when $IL-1{\beta}$ was injected to the mice, enzyme activities of the glucokinase and hexokinase were decreased. But, R-G stimulated induction of enzyme activities of the glucokinase and hexokinase as high as normal group. These results suggested that R-G is highly effective in treatment of diabetes mellitus.